Optima Batteries, ready up sonny 
as for that box, the only problem with TOOmuch air space, is the subs could sound as if they are OVER powered when they are not (trying to push ouit too much air)
Rechecking math
you wopuld want a 32"x14"highx13" deep to get the best sound, that will give you about 1.25" of air space per sub. Remember, you ghave to include the rmeoval of space the sub takes otu inside the box.
Hmm... that box you listed would do fine the more I thik about it. An extra 1/4 cu of air for a small ported design box like that would more than be good for the applciation.
